1. Field of the Invention
The present invention relates to a plating apparatus and a wire inspection method of the same.
2. Description of the Background Art
In recent years, various types of electronic equipment employ printed circuit boards having improved density and reduced size. In manufacture of the printed circuit board, a seed layer that has previously been formed is subjected to electrolytic plating by a plating apparatus in a process of forming wiring traces, for example.
A plating apparatus described in JP 2003-321796 A, for example, includes a plating tank containing a plating solution. An anode is placed in the plating tank. A plurality of rotating bodies are provided outside the plating tank to sandwich a long-sized substrate therebetween. As the plurality of rotating bodies rotate, the long-sized substrate is transported into the plating tank through a slit formed in a side wall of the plating tank. In the state, a voltage is applied between the anode and a region of the long-sized substrate to be subjected to the electrolytic plating. In this manner, the electrolytic plating is performed on the long-sized substrate in the plating tank.
In general, the region of the long-sized substrate to be subjected to the electrolytic plating is electrically connected to a negative electrode of a DC power supply such as a rectifier through the rotating bodies and wires. In this case, the negative electrode of the DC power supply and the plurality of rotating bodies are electrically connected through the wires.
Therefore, a rotary connector, for example, is provided in each of portions where the rotating bodies are connected to the wires so as not to cause the wires to be twisted because of rotation of the plurality of rotating bodies. The rotary connector has a movable electrode capable of rotating with the rotating body, and a fixed electrode that is held still, and a conducting fluid is filled in a portion between the movable electrode and the fixed electrode. The rotating body is connected to the movable electrode, and the wire is connected to the fixed electrode. Thus, the wire can be electrically connected to the rotating body without being twisted even during rotation of the rotating body.
If the rotary connector corrodes, however, the movable electrode may not smoothly rotate relative to the fixed electrode. In this case, the fixed electrode is liable to move according to rotation of the movable electrode of the rotary connector during the rotation of the rotating body. This may result in connection failure such as disconnection or increased resistance of the wire.
The electrolytic plating cannot be performed in the case of disconnection of the wire in the plating apparatus. When a current is controlled to be constant, for example, performing the electrolytic plating in a state of increased resistance of the wire raises the voltage applied between the anode and the region of the long-sized substrate to be subjected to the electrolytic plating. This leads to lower quality of plating. Thus, the wire has to be inspected for connection failure in the plating apparatus before the electrolytic plating is performed on the long-sized substrate.
At a tip portion of the long-sized substrate that is fed from a roll, however, a nonconductive material such as polyethylene terephthalate or polypropylene is formed, and a conductive material is not formed. Accordingly, a closed circuit capable of passing the current therethrough is not formed in the plating apparatus.
Conventionally, inspection of the wire for connection failure was manually performed by a worker using a measuring instrument such as a tester. Such manual inspection is highly inefficient.